<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <link rel="stylesheet" href="bootstrap-3.3.5-dist/css/bootstrap.min.css"/>
    <script type="text/javascript" src="jquery-1.11.3.js"></script>
    <script type="text/javascript" src="bootstrap-3.3.5-dist/js/bootstrap.min.js"></script>
</head>
<body>
<!--一般下拉菜单的设置-->
<div class="dropdown" style="margin-top: 200px"><!--这里的设置dropdown设置为下拉菜单，，dropup设置为上啦菜单-->
    <button class="btn btn-danger dropdown-toggle" type="button" id="xiala1" data-toggle="dropdown" aria-expanded="false">
        Dropdown
        <span class="caret"></span>
    </button>
    <ul class="dropdown-menu" aria-labelledby="xiala1">
        <li class="disabled"><a href="#">action</a></li><!--菜单中的禁用选项=====-->
        <li><a href="#">ffsasdasd</a></li>
        <li role="separator" class="divider"></li> <!--分割线的使用-->
        <li><a href="#">gdzsdawq</a></li>
        <li><a href="#">vdszsdwq</a></li>
    </ul>
</div>
</body>
</html>